Fresh twist in US-EU airline tax row
31 July 2012 Last updated at 09:48 BST
The US Senate's commerce committee is to vote on a bipartisan bill that would make it illegal for US airlines to comply with a controversial EU law on carbon emissions.
Washington is looking to ratchet up the pressure in an ongoing row over the legislation, which will force carriers using European airports to pay extra charges from April 2013.
Mark Gregory reports from New York.